Y-DNA testing is used to trace paternal lines since the Y chromosome is passed from father to son through the generations. It can, therefore, be used to confirm or deny genealogical connections.
Y-DNA Testing of Two Wallace Men
This article discusses the genetic testing which allowed distinction between the descendants of Toliver Wallace (1809-1882) and Lt. William Wallace (ca 1755-1800). It shows that the two early Rutherford County, North Carolina, families are not related along a paternal line.
Cobb County Genealogical Society, 2011 Family Tree Quarterly, Volume 21, Issues 1 & 2, pp. 10-15. Bulletin of the Genealogical Society of Old Tryon County, Volume 39, Issue 2 (May 2011), pp. 52-55.